The present invention relates generally to simulated eye lenses and, more particularly, to simulated diseased lenses and processes of making the same.
Microsurgical operations are highly successful, but they require the surgeon to exercise a great degree of control over the surgical handpiece and yet provide a minimum degree of bodily invasiveness. In ophthalmological microsurgery one known technique for removing cataracts is phacoemulsification. The phacoemulsification technique typically involves the use of a microsurgical handpiece that includes an ultrasonically operative tip that is typically inserted through an incision in the eye; which incision is in the order of about 3 mm. Extreme care must be taken during such surgery to avoid unnecessary damage to other parts of the eye. Phacoemulsification is a procedure that is very demanding of the surgeon in terms of both surgical skill and intraoperative vigilance. In this regard, a surgeon performing such an operation must receive instructions regarding the technique.
It is important that surgeons have the ability to learn and practice the phacoemulsification technique. The surgeon must be able to repeatedly practice the motor coordination skills required to manipulate and emulsify a lens. Towards this end there have been several approaches. One includes using animal eyes (e.g., geese, rabbits, cows and pigs). A shortcoming of this approach is that animal eyes have not developed cataracts. Accordingly, these untreated animal eye lenses are generally inadequate. Thus, the simulation desired for practicing and demonstrating the simulation desired for the emulsification techniques is not as good as is otherwise desired.
Other approaches designed for improving simulation are described in U.S. Pat. Nos. 4,762,495 and 4,762,496 to Maloney et al. Basically, these patents describe the formation of a simulated human ocular system employing an artificial lens phantom. The lens phantom is constructed so as to resemble human cataracts both in terms of hardness and lens translucency. The overall simulated ocular system includes the use of a number of man-made elements that are fitted together such as, for example, a unitary corneal cap and an encapsulated lens and iris. The encapsulated lens includes a wall made of a vinyl film, which is cataract phantom composed of a water-soluble composition designed to be similar to that found in the natural occurring cataract. To retain the same emulsification characteristics a permanent hydrogel material is provided using a cross-linked gelatin. The material is hydrated or provided with proper water sensitivity by the incorporation of a water soluble polymer. The hardness of the artificial cataract is controlled by the addition of fillers of micron-sized glass beads. It is appreciated that the foregoing approach is expensive and time consuming. Further, the degree of simulation is less than entirely satisfactory given the large number of artificial components.
The present invention is directed to improving upon heretofore known techniques for producing simulated diseased lenses, especially cataractous lenses, having degrees of hardness and loss of transparency so that they resemble the various degrees or stages of cataract affliction. Heretofore, none of the known approaches utilize natural animal eyes or other suitably hardened proteinaceous material with the desired hardness and loss of transparency which correspond to various stages of diseased cataract lenses.